Rambam - 1 Chapter a Day

These laws did not only apply with regard to firstborn animals in the era of the Temple, but in subsequent periods of time, as indicated by the fact that Sanhedrin Sa speaks of Rabbah bar Chanah receiving such license from Rav Yehudah HaNasi more than 100 years after the destruction of the Temple.

The head of the Sanhedrin of 71 judges. Even if the expert was a distinguished sage, unless he was granted permission by the nasi, he should not issue such rulings (Yoma 78a).

If there is an expert in the area, a person may not even slaughter an animal with the types of blemishes mentioned in the following halachah without the expert granting permission.

We do not fear that he will intentionally permit the slaughter of an animal that is unblemished. Rather, the fear is that his desire to be free of the obligation to care for the firstborn animal will cause him to make an improper judgment and permit its slaughter when that was uncalled for.

The Shulchan Aruch (Yoreh De’ah 309:2) define this as referring to “men of some wisdom, but not experts.”

Needless to say, this applies to an animal born in the Diaspora (Kessef Mishneh).

If, however, it is not obvious that an animal is blemished, no one other than an expert may grant license for its slaughter.

I.e., an unblemished firstborn.

I.e., after it is established that the animal is blemished, it no longer possesses any sacred status. It must, however, be given to the priests. Nevertheless, this is a far less severe transgression and we fear that some of the common people may violate it.

And thus it definitely no longer possesses a sacred quality and can be eaten by an ordinary person.

For if he intended to take the animal for himself, he could have done so without bringing it to the expert.

Bechorot 28a states that this is a decree, initiated as a safeguard. There are some blemishes in the eye which will change color after the slaughter of an animal and it is possible that a condition that is not truly a blemish will be permitted. Hence to ensure that inappropriate leniency was not granted in that instance, our Sages forbade inspecting all blemishes after the animal was slaughtered.

See Hilchot Pesulei HaMukdashim 19:11.

Which is one of the disqualifying blemishes, as stated in Hilchot Bi’at HaMikdash 7:8.

Kneading the animal’s genital area will force the second testicle into its sac.

Even though the animal did possess a second testicle, since it did not come out despite the kneading process, it is considered as a disqualifying blemish (Rav Yosef Corcus, based on Bechorot 40a).

For perhaps, had the animal’s genital area been kneaded, the testicle would have emerged. If, however, a second testicle is not found, the animal is permitted.

This applies even when in truth the animal was blemished. Since it is forbidden to benefit from it, as stated in Halachah 4, the person who caused it to be slaughtered is considered as one who damaged his colleague’s property and he is responsible for reparations.

A goat or a sheep.

A calf.

For this reason, the person is not required to pay half the animal’s worth.

See Hilchot Nizkei Mammon 5:1-2 which explains that since small animals frequently graze in other people's fields and damage the crops, our Sages forbade raising small animals in Eretz Yisrael. For that reason, the owner is further penalized and the person who permitted the slaughter of the animal is released from responsibility for an additional fourth of the animal's worth.
In the Diaspora, this rationale is not relevant and this further penalty is not exacted and the person who permitted the slaughter of the animal is required to pay half its worth. The Shulchan Aruch, Yoreh De'ah 310:3, states that, in that era, most of the fields in Eretz Yisrael were not owned by Jews. Hence, the laws that apply in the Diaspora apply there. Today in Eretz Yisrael, there is reason to say that the rulings followed in the era of the Talmud should be reinstated.
The Ra’avad offers a different interpretation of the reasons why the owner receives only these amounts. Providing food for large animal costs the owner substantially. Since he will be saving that money, the amount he receives is less. Similarly, the cost of hiring a shepherd for a small animal is great, for it cannot be raised in the settled areas of Eretz Yisrael and must be taken to the distant forests. Hence, the damages required for its loss are less.

For a person should render Torah rulings without charge, emulating the example of Moses our teacher. Thus on Deuteronomy 4:5: “Behold I taught you,” Bechorot 29a comments: “Just as I [Moses] taught you free of charge, you should teach free of charge.” With regard to the entire concept of receiving wages for teaching the Torah, see Hilchot Talmud Torah, ch. 3, where the subject is discussed in detail.

Bechorot 28a states that if a person receives a fee for inspecting a firstborn, an animal should not be slaughtered on the basis of his ruling unless he is “like Ila in Yavneh.” In his gloss to that passage, the Ramban states that Ila was a great authority on blemishes. Everyone would bring their firstborn animals to him and thus he would not have time to perform his work. Hence the Sages granted him license to receive a fee for his services.

In this way, he will have no desire to classify it as blemished, because he will be paid regardless (Bechorot 28b).

In this way, he will have no desire to classify it as unblemished, because he will not receive any extra payment for this ruling (ibid.). Tosafot ask: If so, one might think that he would classify it as blemished so that he would not be forced to inspect it again. They reply: We do not suspect that a sage would permit a transgression to be performed (slaughtering an unblemished firstborn which is a sacred animal outside the Temple Courtyard).

The entire body of the firstborn animal is consecrated and it is forbidden to make personal use of anything from that animal. Because this person is suspect of selling firstborn animals as ordinary property, we take precautions regarding all products that could come from such an animal: its meat, its hide, and its wool.

Even though the concept of the holiness of a firstborn animal does not apply with regard to wild animals, this safeguard is employed, because of the reason stated by the Rambam.

Which could never be endowed with the holiness of a firstborn.

Whitening wool does not involve much time or activity. Hence it is possible that the wool came from a firstborn animal.

I.e., that it appears that it has been taken directly from an animal. Thus there is a likelihood that the wool came from a firstborn.

These three activities all take time and hence, the product is permitted for the reason the Rambam proceeds to state.

For this is a matter that could be known by his neighbors, workers, and the like and could easily become the topic of conversation in a rural environment.

See Hilchot Mechirah 16:12. Even though the person benefited from the forbidden substance, after he realizes that it is forbidden, his regret is so great that the benefit is not considered significant.

And thus slaughtered as a sacrificial animal.

If it was discovered to be treifah before it was skinned, the hide must be buried together with the meat (Kessef Mishneh).

Hilchot Pesulei HaMukdashim 19:9.

As is the law concerning a firstborn animal that died. Since it was treifah, its slaughter is not significant and there is no difference between it and an animal that died naturally.
One might ask: In Chapter I, Halachah 3, it was stated that a blemished firstborn animal is a priest's private property and he may do with it as he sees fit, even feed it to a gentile. Why then can the animal here not be given to a gentile? In resolution, it can be explained that once the firstborn is given to a priest. and he may partake of it, he may do with it as he sees fit. In this instance, however, the priest never had the license to partake of the firstborn. Hence, he cannot use it for other purposes.

Rabbenu Asher differs and maintains that it is forbidden to benefit from the hide and it must be buried, even in such a situation. His opinion is cited by the Tur and the Shulchan Aruch, Yoreh De’ah 307:2.

I.e., when an unblemished animal was offered as a sacrifice or when a blemished animal was slaughtered according to the ruling of an expert.

As explained in Hilchot Me’ilah 1:7-9, there is a Scriptural prohibition against shearing a firstborn animal. This prohibition continues to apply even if the animal was blemished. Wool which is shed by an animal is not, however, forbidden by Scriptural Law. Nevertheless, Halachah 10 of that source states that wool shed or removed from a firstborn animal is forbidden for the reason stated by the Rambam.

Once a blemished animal is permitted and slaughtered, its wool may be used.

In contrast, we assume that a person will offer a sacrifice that comes to secure atonement as soon as possible, for he sincerely desires the atonement.

Chapter 1, Halachah 8.

I.e., the wool was already severed from the animal’s hide, but remained entangled with its other wool.

Since wool that was shed during an animal’s lifetime is forbidden only by Rabbinic decree and, in this instance, it is not apparent that the wool was shed during the animal’s lifetime, our Sages ruled leniently.

Generally, when a forbidden substance that is dry becomes intermingled with a larger amount of a permitted substance that is dry, since the majority of the mixture is permitted, the forbidden substance is considered insignificant. Therefore the mixture may be used. This, however, does not apply if the forbidden substance is an entity of significant importance. Since it is important, it is never considered to be an insignificant element of the mixture. Therefore is never permitted regardless of the amount of the permitted substance. See Hilchot Ma’achalot Assurot 16:9.

In his Commentary to the Mishnah (Orlah 3:2), the Rambam translates the term sit into Arabic. Most commentaries interpret his statements as meaning “the distance between the top of the thumb and the next finger [when the fingers are spread out]. This is one-sixth of the distance between the thumb and the middle finger [when the fingers are not spread out].” Rav Kappach notes that in fact such a calculation will not be accurate. He interprets the Rambam’s words as defining a sit as half the distance between the index finger and the middle finger when spread out. This he maintains is two thumbbreadths.
In his Commentary to the Mishnah (Shabbat 13:4), the Rambam differentiates between “the width of a sit” and “the full length of a sit.” As indicated by Hilchot Shabbat 9:20, “the full length of a sit” is two thumbbreadths. In contrast, as stated (ibid.:7), “the width of a sit” is two thirds of a zeret, i.e., three thumbbreadths.

This ruling is based on the same principle as the first clause. Since the full length of a sit of wool is a significant entity and it is not distinct and thus cannot easily be removed, the entire garment is forbidden.

A consecrated entity must be redeemed before it can be used for ordinary purposes. Since the wool from the consecrated animal could be redeemed and then it would be permitted to use the entity, it is never considered to be insignificant. The rationale is that there is no reason to permit the entity because it is insignificant when there is a way to cause it to be permitted in a manner that resolves all difficulties (Kessef Mishneh in explanation of the Ra’avad; see Hilchot Ma’achalot Assurot 15:10).